Effect of cranial suture autotransplantation from metopic to coronal suture

The aim of this study was to determine the outcome of autotransplanting part of the metopic suture to a defect in the coronal suture in a pig model and to explore further the concept of functioning and nonfunctioning recipient sites. The authors harvested 15-mm x 10-mm bone grafts, incorporating a part of the metopic suture, in 10 Yorkshire pigs under general anesthesia. The authors immediately autotransplanted the grafts to a surgically created defect along the line of the coronal suture. Both donor and graft were either covered with pericranium or left bare. Radiopaque titanium markers were inserted to assess growth 1) of the transplanted suture; 2) across both coronal sutures; and 3) across the metopic suture. Serial radiographs were taken immediately after surgery and at 3-week intervals. The pigs were then killed at 21 weeks. The cranium was harvested, and blocks of donor site and graft were taken, incorporating the embedded titanium markers. Histologic analysis confirmed graft take in all pigs. All grafts continued to function as active cranial sutures with no growth disturbance compared with the contralateral coronal suture (P = 0.953). There was also regeneration of the donor defect, as confirmed by histologic analysis, with no growth disturbance across the metopic suture (P = 0.972). Pericranium did not alter graft take or subsequent growth (P = 0.964). However, pericranium resulted in a much smaller defect (P = 0.045). These results show that after autotransplanting a cranial suture to replace another cranial suture, the graft continues to grow and function as a cranial suture to meet the functional demands of the new recipient site. Pericranium has a significant effect on calvarial regeneration but does not affect cranial suture autotransplantation.